Once an air-fuel mixture has been drawn into the combustion chamber of an internal combustion engine, the mixture is ignited and is burned until it is discharged to the atmosphere. However, not all of the air-fuel mixture is completely burned and discharged. A portion of the unburned mixture during the compression stroke and a portion of the burnt gas during the power stroke leaks through the clearance space between the piston and the cylinder wall into the crankcase. The leaked gas is commonly referred to as blow-by gas. The blow-by gas needs to be discharged outside of the engine partly because it deteriorates the quality of the lubricating oil in the crankcase and partly because the leak pressure tends to increase the pressure in the crankcase. Excessive pressure in the crankcase may cause leaking of the lubricating oil and the back flow of the lubricating oil into the cylinder head. Therefore, a means is needed to remove blow-by gas from the crankcase. Normally, the blow-by gas is returned to the combustion chamber instead of direct injection into the atmosphere in order to avoid air pollution concerns. The blow-by gas is directed through an air-oil separator before entering the combustion chamber so that lubricating oil may be separated from the air before combustion.
Prior art air-oil separators have utilized labyrinth type designs which allow the oil to collect on the walls of a housing through a series of baffles. The oil drains downwardly to a lowermost point on the separator and is directed to the crankcase through an opening. Consequently, the air is separated from the oil and is continuously directed inward during the oil removal process. The resultant "separated" air is mixed with fresh air entering through the air filter for use within the combustion chamber. The labyrinth designs rely totally on the baffles to remove the oil from the air and can be expensive and complicated to manufacture.
Prior art air-oil separators typically use a spring pull-through device for attaching the air filter housing to the air-oil separator. The spring pull-through device is easily twisted and distorted during installation and subsequent maintenance procedures.
The present invention is directed at overcoming the problems as set forth above.